Jupiter 11/23/2012

EDIT: In the original post I uploaded a scanned image which was pretty bad. I took a photo of my sketch which is much better and edited it in.

It's been a while since I last posted here, weather being the biggest reason I haven't sketched. Last night I pulled out the Dob and binoviewer and let them cool while I helped clean up. After the food and wine had a chance to settle I went outside to observe. Wow, what a gorgeous night with pristine conditions. With the GRS positioned well, I decided to sketch Jupiter to try and capture the great view. Rather than ramble on I'll just post my sketch. Thanks for looking.

Ed D

OOOPS: I titled the post 11/23/2012, which should read 11/22/2012

Attached Files

Ed, a little over exposed. From what I can see, you captured the tawny hue north of the NEB. To me, seeing that was the bridge to really seeing Jupiter in colors. Everything else looks great and well placed, just can't really make it out that well.

Unfortunately, my scans never come out looking like my sketches. I agree this one looks very 'overexposed' in comparison to the real thing. The north cap should be more homogenous with very faintly discernable streaks, while the southern cap should be fairly uniform with the streak above it not so prominent. I need to play with my scanner to see if there is anything I can do to get better results. This doesn't do any justice to my sketch. Oh well.

Ed, the sketch is great! I especially love the angle of presentation, which adds to the realism. I do agree that the scan appears blown out, I'm guessing the contrast is too high on the platen capture. What scanner do you use? And how do you capture your scan? Are you using the scanner buttons, or using the driver software from the computer desktop?

Yea, Ed, I can't scan anything. Don't even own one and no longer work with one. That's why I went to PC paint programs to get sketches up quickly. Besides, your hand drawn sketch is a thousand times cleaner than mine. Mine are garbled with features, question marks, and notes.

But, yes, the later image is much better. Thanks. And you description above sounds like you had a great view. Those streaks in the northern region are not so easy. The south is a tad easier.

Here's one of mine from tonight. Sorry it's a horrible image. But maybe you can see why they don't get scanned and posted as it. Tomorrow, all those notes will coalesce into a color sketch.

A week ago with my 70mm I made a sketch with of the same CM under 5/5 seeing at 120x. It was funny kinda actually. One entire side of the SEB was virtually missing as the lower contrast all but rendered it gone. Festoons were a slightly dark edge to the southern edge of the NEB and nary a classic sweep or projection. Just a darker edge to that side of the belt. I made a finished sketch anyway because what I did see was worked for but it isnt anything like your piece or others. Im fond of it regardless because its a GREAT scope doing a Great job but too tall an order in light of the seeing.

Your piece has a nice smoothly blended black and grey luminosity I see often in Michael Rosalinas work too. Clean fresh and concise. Its a pleasure to see smoothly executed rendering.

thanks for posting your drawing. One thing though, Jupiter is decidedly flattened, so an elliptical template is much more accurate (some available here http://www.britastro...03obsforms.pdf) A good effort though!

Thank you all for the very positive and wonderful responses. I have been mainly using my 6" f/8 Dob. For planetary, specifically Jupiter and Saturn, I like mags of 160x (Agena 7.5mm ED) and 200x (Astro Tech LER), depending on conditions. Most of my planetary observing is done from my home in Miami. The night I made this observation the GRS was a very pale white oval with the dark feature in the center, which looked much like a fried egg.

When I make a sketch I start by drawing a circle on the paper using an appropriately sized can from the kitchen pantry. I know that's crude, but it works for me. However, the more I observe Jupiter the more I see it's distinctive flattened shape. I think I'm going to make a template from a slightly flattened piece of tubing depicting the appropriate 7% distortion - no big deal to cut and smooth a piece of aluminum tube and shape it in the vise.

I have come to really enjoy planetary and lunar observing from my home, reserving most of my DSO observing when I get to go to dark skies. I'm sure the heavy LP is a major influence in this.

Ed, I do exactly the same to prep a template for sketching, grab a can from the kitchen and make a circle. LOL

For the final, I made a template in powerpoint. Insert a real, current image of Jupiter and place an ellipse over it's circumference. You can even lay guides for each zone.

To cover all that mess up, you can apply a mask (using the exact same ellipse you used for Jupiter's circumference.) Maybe you could work that into your scanned sketch. Dunno. Or just print the template and do the final sketch on it.

Yes, 160x to 200x is best for me, too. Best compromise between image scale and contrast in a 6", IMO.